Method and apparatus for establishing a packer

ABSTRACT

A method for establishing a packer around a tubing in a down hole location comprising forming an obstruction in the annulus between the tubing string and the well bore at the location where the packer and seal is to be formed, moving a pumpable slurry of sand and water into the annulus above the obstruction, and allowing the sand to settle by gravity down upon the obstruction and fill a portion of the annulus thereabove. Apparatus employed in the practice of the method includes a tubing string open at the lower end, a doughnut device around the tubing string above the lower end thereof and forming an obstruction in the annulus therearound, check valves in passages formed through the doughnut, and deflection means below the lower end of the tubing string for deflecting a pumpable slurry of sand and water upwardly through the passages in the doughnut into the annulus thereabove.

Shirley METHOD AND APPARATUS FOR ESTABLISHING A PACKER [76] Inventor: Billie J. Shirley, PO. Box 20648,

Oklahoma City, Okla. 73120 [22] Filed: Sept. 10, 1973 [21] Appl. N0.: 395,749

[52] US. Cl 166/285, 166/179, 166/315 [51] Int. Cl. E2lb 33/12, E2lb 33/13 [58] Field of Search 166/285, 287, 290, 286, 166/292, 281, 293, 294, 295, 179, 192, 117, 278, 276, 51, 315

[56] References Cited UNITED STATES PATENTS 1,895,905 1/1933 Young 166/290 X 1,979,802 11/1934 Kinley... 166/192 2,080,406 5/1937 Allen 166/287 2,465,564 3/1949 Abrams. 166/285 X 2,597,554 5/1952 West 166/278 2,777,679 l/1957 Ljungstrom 166/285 3,134,440 5/1964 Nelson 166/290 X 3,252,514 5/1966 Joy 166/179 X 3,262,499 7/1966 Fleming... 166/278 3,630,277 12/1971 Smith 166/51 [111 3,866,681 [451 Feb. 18, 1975 3,664,421 5/1972 Urbanosky 166/285 X Primary Examiner-Stephen J. Novosad Attorney, Agent, or Firm-Laney, Dougherty, Hessin & Fish [57] ABSTRACT A method for establishing a packer around a tubing in a down hole location comprising forming an obstruction in the annulus between the tubing string and the well bore at the location where the packer and seal is to be formed, moving a pumpable slurry of sand and -water into the annulus above the obstruction, and allowing the sand to settle by gravity down upon the obstruction and fill a portion of the annulus thereabove.

4 Claims, 3 Drawing Figures METHOD AND APPARATUS FOR ESTABLISHING A PACKER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to packers and plugs of the type used to seal and block the annulus around a tubing string in a well bore at a selected location in the well bore.

2. Brief Description of the Prior Art Various types of packers have been employed as tools useful in the production of oil and gas, and have included such structures as inflatable, balloon-type expandable members carried around the perimeter of the tubing string and inflatable to a size such that the packer sealingly contacts the casing of the well, or the well bore, to form a seal or obstruction around the tubing string at the location of the packer. In some instances, metallic packers having teeth or serrations formed at the outer edges thereof have been carried on the tubing string, and have been capable of being set against the casing or well bore by a mechanism carried within or on the tubing string and operable by fluid pressure, or by mechanical linkages extending from the well head. Steel or other metallic packers, as well as packers of the inflatable type generally, when considered in association with the mechanisms which are required in their use, will occupy a substantial diametric dimension in the well bore, making it difficult to employ such packers in very small diameter casing strings or in other confined spaces in the well bore. Moreover, in those instances where the packer is to be set at extreme depth in the deep well bores, a heavier construction is required, and the bulk of the metal or material required for inclusion in the packer is such that even greater diametric sizes are required, sometimes limiting the types of packers which can be utilized at these greater depths.

In substantially all cases, the packers and their associated operating mechanisms are relatively expensive in construction and are, to varying degrees, susceptible to mechanical failure over extended periods of time as they are subjected to the cutting and abrasive action of sand entrained in production fluids and to the fluctuations in pressure which are experienced over extended service life in a producing well environment.

Further, where rubber or synthetic resin packers are provided, they are soon destroyed or damaged beyond functional effectiveness in very hot (deep) wells. Also, this type of packer is totally unsatisfactory for the completion of wells presently being bored for the purpose of tapping and utilizing geothermal energy sources in California and other locations.

BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention comprises a very simple, yet highly reliable packer or plug which can be quickly and easily established around a tubing string in a well bore. The packer may be described as a sand plug or packer and consists, in its most basic form, of a rigid supporting and obstructing structure overlain by. a bed or body of sand which rests upon the rigid obstructing structure, and extends between the tubing string and the surrounding well casing or well bore, as the case may be.

The presence of sand in a downhole environment in the oil and gas production technology is frequently considered a deleterious or undesirable factor. It is usually an objective of production practice to eliminate or suppress sand production from the well, and sanding of pump parts or abrasion of tools is to be avoided. In the present invention, however, I use the unique bridging effect of sand grains for the highly useful purpose of establishing an effective packer or plug which will seal the annulus around a tubing string over extended periods of time.

The present invention further comprises a method of forming a sand packer in the annulus surrounding a tubing string which includes the steps of initially forming a rigid, sand supporting obstruction around the tubing string in a position to block the flow of sand past the obstruction and downwardly in the annulus. A slurry of sand and water is then placed in the annulus above the obstruction, and the sand is allowed to settle by gravity onto the obstruction to form a bed or plug at this location. The water is then preferably removed, but it need not be.

An important object of the present invention is to provide a very inexpensive down hole sealing and packing apparatus for use in deep wells for establishing a packer or seal around the tubing, and between the tubing and a surrounding casing or bore hole.

An additional object of the invention is to provide a very effective, tenacious seal and packing around a tub ing string in a well bore.

An additional object of the invention is to provide a packer for use in conjunction with tubing strings extended into a well bore, which packer is effective in establishing a packing or seal around the tubing string, buth which occupies a much lesser diametric dimension than packers hereinbefore in use.

A further object of the invention is to provide a packer and seal for use in conjunction with tubing strings extended into a down hole environment, which packer is less susceptible to corrosion and wear than metallic or rubber packers heretofore in use.

Another object of the invention is to provide a packer which can be placed and utilized by operators having a minimum amount of technical knowledge and experience in the setting of down hole packers.

A further object of the invention is to provide a sand packer and seal for use around a tubing string, which packer and seal requires a minimum of operating mechanism for its effective utilization.

An additional object is to provide a packer for use around a tubing string in a down hole environment in which very high temperatures are encountered and the packer must effectively withstand such temperatures.

Additional objects and advantages will become apparent asthe following detailed description of the invention is read in conjunction with the accompanying drawing which illustrates the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view through a portion of a cased well bore depicting the packer of the present invention in place in the well bore, and used to seal between the DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring initially to FIG. I of the drawing, a bore hole is extended into the earth 12 to a substantial depth for the purpose of producing water, oil, gas or other minerals from a subterranean formation. The bore hole 10 is cased by means of a suitable string of tubular casing 14 positioned in the bore hole, and the casing is cemented therein by means of a column of cement 16 as hereinafter described. Positioned in the lower portion of the well bore 10 and within the casing 14 is a column of mud 18 which has been utilized in completing the well for forcing the cement up into the annulus'between the casing 14 and the well bore 10.

Extending downwardly in the casing 14 is an elongated tubing string designated generally by reference numeral 19. The tubing string includes a tubing section 20 which is threaded into a tubular obstruction member 22. It should be pointed out that other forms of structure than the tubular obstruction member 22 can be used in the practice of the invention, the primary consideration here being that a tubular member be provided having a bore therethrough and having an obstructing ring or doughnut of some type formed around the outer periphery thereof which seals all, or a major portion, of the annulus between the bore therethrough and the surrounding well casing.

In the illustrated embodiment of the invention, the tubular obstruction member 22 includes an elongated tubular section 24 carrying an enlarged body portion 26 which is diametrically dimensioned to be very slightly undersized with respect to the casing 14 so that the tubular obstruction member can be lowered in the casing from the surface without interference by joints or anamolies in the casing string. It will be noted in referring to FIGS. 1 and 2 that the upper side of the body portion 26 slopes downwardly and outwardly. It should also be here pointed out that the body portion 26 can be made quite small in diameter to allow passage into casing strings or other tubular members of small diameter, or into an open well bore of small diameter. This capability constitutes one marked advantage of the present invention.

The body portion 26 is provided with a pair of fluid passageways 28 and 30 extending therethrough along lines parallel to the longitudinal axis of the tubular obstruction member 22, and a pair of check valves 30 and 32 are provided at the upper ends of the fluid passageways 28 and 30. The check valves 32 and 34 are arranged to check against fluid flow downwardly through the fluid flow passageways, and to open to permit upward flow of fluid through these passageways. In the preferred embodiment illustrated, a pair of ball stops 36 and 38 are provided over the check valves 32 and 34 and function as stops to prevent the check valves from moving out of the tubular body portion 26 under the impress of fluid pressure.

OPERATION AND USE In the use of the illustrated embodiment of the invention, a pumpable slurry of sand and water is made up at the surface. It is assumed, of course, that an effective seal and packer is to be established at a location just above the body portion 26 of the tubular obstruction member 22 in the well bore. Such seal and packer is to function to seal the tubing string in position with a firm the tubing string and the casing.

The sand and water slurry is pumped down the tubing string through the tubing section 20 and through the tubular obstruction member 22. The pumpable slurry is then diverted upwardly by contact with the upper surface of the mud column 18, and will flow up through the two fluid passageways 28 and 30 formed through the body portion 26 of the tubular obstruction member. The check valves 32 and 34 will not obstruct such flow so that the slurry will ultimately be positioned above the body portion 26 of the tubular obstruction member 22in the annulus between the tubular section 24 and the casing 14. The amount of the water and sand slurry which is pumped into this location will vary and will depend upon the depth of sand which is to be used in establishing the packer and seal. In general, relatively little sand must be established in the sand bed which will constitute the packer and seal, since the bond and seal afforded by the sand is of high strength, and the sand performs a wedging action in sealing the body portion 26 against axially upward movement in the casing 14.

After the sand and water slurry has been pumped into the annulus between the tubing section 24 and the easing 14 above the body portion 26, the sand settles by gravity and the water is allowed to drain slowly from the sand around the body portion 26, or it may be quickly removed by the use of an appropriate suction device extended into this annulus from the surface after the sand has settled out of the water, and established a bed resting on and immediately overlying the body portion 26 of the tubular obstruction member 22. Actually, the water portion of the slurry does not need to be removed at all, since the only requirement for the establishment of the packer and seal is that the sand be permitted to settle into a gravity packed bed overlying the body portion 26. I have found that the sand, when allowed to accumulate and form a bed in this manner, is almost as effective as if a cement plug were formed at this point.

Although the precise mechanism for the accomplishment of the great strength and durability of the packer and seal formed in this manner is not precisely understood, I believe that the small, generally spherical particles of sand undergo a bridging mechanism in which, in their settled and packed bed condition, they cannot be displaced by axial pressures, either in a mechanical sense resulting from trying to lift the tubing string upwardly within the casing, or from fluid pressures acting from below or above.

At a time when it is desired to release or remove the sand packer and seal, this can be accomplished by circulating water into the annulus between the tubing string and the casing 14 above the sand packer by the use of an overshot wash pipe used to direct water into this annulus and positioned at the surface.

Such washing action will gradually pick up and remove sand from the top of the bed constituting the packer and seal, and eventually, such washing will wash away the sand to the point where the tubing string can be pulled.

Although a preferred embodiment of the invention has been herein described in order to clearly illustrate to those skilled in the art, the principles underlying the invention, it will be understood that other forms of structure can be used in the placement of the sand bed constituting the packer and seal of the invention, and that slight variations in the method described herein can be employed without departure from such basic principles.

Changes and innovations of this type are therefore deemed to be circumscribed by the spirit and scope of the present invention except as the same may be necessarily limited by the appended claims or reasonable equivalents thereof.

What is claimed is: 1. A method for establishing a packer around a tubing in a down hole location comprising:

forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed; moving a pumpable slurry of sand and liquid down through the tubing to a point below said obstruction; then diverting the slurry upwardly through passageways in said obstruction into the annulus above said obstruction; and

allowing the sand to settle by gravity down upon the obstruction to fill a portion of the annulus.

2. A method for establishing a packer around a tubing in a down hole location comprising:

forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed;

moving a pumpable slurry of sand and liquid into the annulus above the obstruction;

allowing the sand to settle by gravity down upon the obstruction and fill a portion of the annulus; and

pulling the tubing and obstruction upwardly in the well bore after the sand has settled to more firmly lock the sand in packing position.

3. A packer for use in packing around a tubing string in a well bore comprising:

a rigid supporting and obstructing structure which includes an enlarged body portion secured in the tubing string and having downwardly and outwardly sloping shoulders at the upper side thereof, said enlarged body having a bore therethrough communicating with the bore of the tubing string and further having at least one lfluid passageway extending therethrough from the lower side to the upper side thereof; and

a body of laterally supported sand resting on top of the obstructing structure.

4. A method for establishing a packer around a tubing in a down hole location comprising:

forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed;

placing a body of sand on top of said obstruction and around said tubing in the annulus around the tubing; and

pulling the tubing and the obstruction upwardly in the well bore after the sand has settled, to more firmly lock the sand in packing position. 

1. A method for establishing a packer around a tubing in a down hole location comprising: forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed; moving a pumpable slurry of sand and liquid down through the tubing to a point below said obstruction; then diverting the slurry upwardly through passageways in said obstruction into the annulus above said obstruction; and allowing the sand to settle by gravity down upon the obstruction to fill a portion of the annulus.
 2. A method for establishing a packer around a tubing in a dOwn hole location comprising: forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed; moving a pumpable slurry of sand and liquid into the annulus above the obstruction; allowing the sand to settle by gravity down upon the obstruction and fill a portion of the annulus; and pulling the tubing and obstruction upwardly in the well bore after the sand has settled to more firmly lock the sand in packing position.
 3. A packer for use in packing around a tubing string in a well bore comprising: a rigid supporting and obstructing structure which includes an enlarged body portion secured in the tubing string and having downwardly and outwardly sloping shoulders at the upper side thereof, said enlarged body having a bore therethrough communicating with the bore of the tubing string and further having at least one fluid passageway extending therethrough from the lower side to the upper side thereof; and a body of laterally supported sand resting on top of the obstructing structure.
 4. A method for establishing a packer around a tubing in a down hole location comprising: forming an obstruction around the well bore contained-tubing in the annulus therearound at the location where the packer is to be formed; placing a body of sand on top of said obstruction and around said tubing in the annulus around the tubing; and pulling the tubing and the obstruction upwardly in the well bore after the sand has settled, to more firmly lock the sand in packing position. 